This invention relates to folding structures consisting of interconnected extended tubular elements. More particularly, this invention relates to portable folding structures which can be extended horizontally or vertically, that can be used for product display or as supports for raised loads, such as for instance platforms, walkway bases, technical pavements, rostrums, stands, boxes. These structures comprise a plurality of interconnected parallelepiped cells in which the sides faces of the parallelepiped are defined by a pair of tubular elements interconnected by a scissors-connector. In these structures, each extremity of the extended tubular elements which constitute the pair of scissors-connected elements, is inserted by rotation into a seat in an articulated universal joint, also parallelepiped in form. The universal joint presents, on one of the larger faces, a hinging seat corresponding to each side face, and can therefore accept up to four extremities of tubular elements. In the case of structures that must bear heavy loads, a variation to the embodiment described above has been used for some time in which the universal joints provide for a fifth seat on the surface of said face into which is fixed a tubular element, within which another tubular element of smaller diameter is inserted as a sliding fit and whose extremity is inserted into the face of a similar universal joint. The tubular element inserted into the face of the universal joint is fixed and is stopped against the opposed joint into which is inserted the extremity of the element that slides inside.
It is often necessary to arrange for exhibition structures or raised support higher than is attainable with the single structure. In this case, more identical (or similar) structures are superimposed such that, in the overlap, the upper faces of the universal joints of the underlying structure are matched to the corresponding lower faces of the upper structure.
Devices are known to increase the height of the exhibition or support systems mentioned above. For instance, an exhibition system that could give rise to structures of different height is described in European Patent EP-A-0 419 006.
The structure described in this patent is complex, provides for a plurality of articulated elements and therefore requires long assembly and dismantling times.
The system proposed in European Patent EP-A-0 884 425 provides for uniting the joints of two structures by connecting the extremities of the two telescopic elements, for instance by means of screw or pin systems.
This system also presupposes complex and onerous setting-up operations, as well as relatively long dismantling and assembly times.